<!doctype html>
<html>
<head>
	<title>demo</title>
	<meta charset="utf-8">
</head>
<body>
<p style="color:blue;">测试文字</p>

<p>wsw</p>
<p>lijia</p>


<script type="text/javascript">
	var num = 1;
	var sum = 0;
	while(num <= 89){
		sum += num++;
		// if (sum >=4000) {console.log(num)};
	}

	console.log(sum);
</script>
</body>
</html>